Combustion control system



. DeC. 12,- 1939. l y Q ,l- BYRNE 2,183,184

COMBUS'IION CONTROL SYSTEM ATTORNEY.

De@ 12, 1939. G.;J. BYRNE 2,183,184

COMBUSTIN CONTROL SYSTEM Filed Oct. 5, 1936 2 Sheets-Sheet 2 Pressure opera/eo srv/c/a 26 INVENTOR Gear ye j yrne BY ATTORN EY Patented Dec. 12,' 1939l l alsaisi `ra'rlfju'r carica faisegi'sfi" ooivmcs'ricN comincil sxs'rnivr George '.iosepth Byrne, Chicago; Ill..v

1 Application october' 5,

193e.. semi No. 104,035l

5 ola-img. (ci. 11o- 49) `r l .This invention relates means forsuppl'ying I ainfor the combustion of fuel in afurnace,v particularly coal. l

l Itis an object of the present invention to pro- 5 videv an.; air supply arrangementgwherebythef amount of excess air that might be supplied over that necessary foreffective combustion'of the fuel is reduced to a minimum and whereinthe heat of the flue gases is Autilized to pre-heat orincrease .10 the temperature of the air supplied forfcombus-x tion of the coal, thereby increasing .the efficiency of combustion.

It has heretofore been proposed tov provide air supply means for furnaces with arrangements for 15 withdrawing uegases from the stack or the like, mixing them with air,` and then introducing such mixture into .the furnace. with such anv arrangementthe increase in eii- .eiency is'quite small. When dealing with cheaper' 520]. grades of coal, especially such grades as produce a good deal of smoke or soot, the amount of avail-- able Aheat which is lost up the chimney is considerable.` lpropose an varrangement whereby the major portion of such heat is saved. When a es'. major portion of the flue gasesare extracted from the -iiue and recirculatedthrough the furnace there is 'but a slight increase in overall heat efciency because, I have found, the recirculation does not result in complete utilization of the avail- :9,0 able energy.

I have discovered that lif steam is injected into u or intimately lmixed or commingled with the moving flue gases the physicalor other changeswhich result frorn'such` injection and mixing are such :i5 thattheheat energy available in such an1ixture appears. to loe/more readily extractableg It' is therefore,one of the objects of the present invenl tionwto provide for the injection of steam into the. iiue products of a furnace and to mix there- .m with a quantity of fresh air, thereafter circulating the resultant product to and through the' furnace.

It is astill further object of the present invenv'tion to provide -almechanical layout whereby the air supply means may readily be changed, to. by-

45 pass the yiiue gas 'circulating system, as may be.'

' "Figure l .is a diagrammaticv view, in partial section,` illustrating one embodiment ofthe present.

I have found that Figurey 2 is' an enlarged longitudinal sectional view througha portion of theiiue gas ducts etc.

ofthe system of Figure 1;

` Eigure 3 is an enlarged end view from the posif 'tion ofthe line --of Figure 2;

' .Figure e is afragmentary view taken along th line d-li of FigureZ;y

'Figure 5 isa fragmentary sectional view taken along the line 5-5 of Figure 4. f` Figure 6 is a vfront elevation of the furnace an the apparatus shown in Fig. l, and

Figure 7 is a diagrammatic view showing the f electrical 'control-used inoperating the 'system in the .preferred manner.

.Reference may now be had more rparticularly to Figure 1.1 .In this figure I have showmat' l, .a

.roi

conventional coalfbur'ning furnace for generating steam, as for domestic heating purposes. The

` motorfdriven fan Il is'provided for supplying air tothe furnacel for combustion "of the coal.- The outlet side of .thefan is connected to the furnace to deliver air thereto below the grate. `The inlet side ofthe fanis `connected to a conduit 5 which leads to a damper compartment 6 having.. a',

`damper .l therein. At its left vhand `side the damper'compartment opens to the atmosphere,

' the extent of opening being controlled by a ported disc '3 which maybe turned-to uncover greater or lesserareas'of the openingat the left hand end f of the damper compartment G. At its right-hand end the damper compartment has connected thereto a duct" iii. The damper. 'i connects the conduit 5 'selectively to the duct l0 or to theatmospheric opening 8, depending upon the positionfof the damper. va pivot ll 'and controlled automatically through a handle l2 or manually 4through a handle i3.

The handle I3 isweighted, as indicated at'li., so lthat the damper 'i normally tends toi assumea position opposite tothat illustrated in Figure 2,y to which it is moved by automatic' means to'loe,

presently described.

The duct l@ isconnected to asteam mixing chamber i8 which in turn is connected by meansof 'apipe i9 tothe stack 2, the pipe i9 opening in The damper is pivoted about L,

the stack and terminating flush with the inner wall of the stack 2, VThe steam mixingchamber has .two similar sets of rsteam inlet pipes 2i! and 2l each of which is provided with a-number ofl small-holes forv discharging steam into the cham-.

tion to control the extent of air movement through the opening 23, the construction of the disc 24 `being identical with the disc 8. A baffle 25 is Xed in the steam mixing chamber I8 adjacent to the air inlet opening 23 to prevent escape of the products of the iiue through the opening 23.

An electromagnetically controlled (solenoid) valve 28 controls the ow of steam to the steam inlet pipes 20 and 2i, the valve being controlled by a pressure operated electric switch 29. The switch 29 is arranged to close its circuit when the pressure drops below two pounds, and maintain the circuit closed until the pressure reaches some value, say, ten pounds, after which the circuit opens and remains open until the pressure has dropped to its minimum value of two pounds, the steam being supplied through a pipe 30 connected to the boiler.- The switch 29 also controls the circuit to the motor 4. Thus when the pressure drops below its requisite minimum value the switch 29 closes and thus establishes a circuit for the motor driven fan i and for the solenoid valve 28 which then opens for the purpose of admitting steam to pipes 2D and 2! and to the pipe 39 for the purposey hereinafter described. The fan starts and draws flue gases from the flue through the steam mixing chamber I8 where the gases are mixed with steam. As the gases move through the steam mixing chamber` they draw in air through the air inlet 23. The resulting mixture then passes through the damper compartment 6, through the conduit 5 to the fan and thence into the furnace.

A steam pressure device is provided for moving the damper 'I to the position indicated in Figure 2 and to this end is connected through pipe 39 with the outlet side of the solenoid controlled valve 28. The steam pressure device 35 acts upon a lever 36 which is pivoted at 3l, and swings the same counter-clockwise to draw a chain 38 downwardly, thus swinging the handle I2 in a clockwise direction to move the damper I to the position indicated in Figure 2. A counter-weight at the right hand end of the lever 35 serves to swing the lever in the opposite direction. When there is no vsteam pressure on the device 35 the counter-weight` maintains the left hand side of the lever 35 raised, thus permitting the Weight I4 to swingvthe damper l' against a stop 40. Whenthe fan motor It is started, as by manual operation, in the morning when there is substantially no steam pressure, the fan draws in air from the atmosphere by way of the ported disc 8. At this time the damper l is in a position against the stop 49 and therefore there is no recirculation of flue gases. The steam operated device 35 requires a pressure of almost two pounds of steam before it can operate the lever 36 against its counter-weight. At this time the switch 29 maintains the valve 28 open so that as the steam pressure is being built up a gradually increasing pressure is being applied to the steam device 35 and more and more steam is admitted to pipes 2U and ZI. When the steam pressure reaches a value of approximately two pounds the device 35 operates and causes the damper 'I to swing. to the position illustrated in Figure 2. The fan now draws in ue gases, which are being mixed with steam. When the pressure reaches the maximum value for which the switch 29 has been set the switch opens the circuit for the electromagnetically controlled valve 28 thereby shutting ofi the steam to the pipes 29 and 2|. At the same time steam is shut off from the device 35 so that the counterweight on the lever 36 now swings this lever counter-clockwise to permit the weight I4 to move the damper 'I against the stop 40. The opening of the switch 29 also opens the circuit to the motor operated fan or blower 4. It is therefore seen that when the motor is not operating, the damper 'I is closed against the stop 40 and thus prevents a back feed of `flue gases which might otherwise escape into the basement. When the steam pressure in the boiler drops to such a value that the switch 29 again closes its circuit, thus again opening the valve 2S, the steam device 35 is a-gain operated to shift the damper 1 to the position illustrated in Figure 2.

A major portion of the smoke and flue gases isvdrawn from the stack 2 through the steam atomizing chamber and mixed with a small amount orair and a small amount of steam. There appears to result a physical change in the condition of the smoke particles by reason of the admixture cf vsteam or vapor therefrom andl the air by intimate commingling thereof with one another and with the smoke particles, so that upon repassage through the furnace, those combustible particles of the smoke which are contained therein are consumed and substantially no smoke is emitted from the stack; also the heat from the steam and from the exhaust products serves to pre-heat the air drawn in to eilect combustion. I have found that if the steam supply to the pipes 20 and 2l is cut oif the efficiency of combustion is substantially reduced. I have also found that if the steam is introduced into the steam mixing chamber in a form other than ne jets the efficiency vof combustion is also reduced. It is for this reason that the pipes 2D and 2l are provided with a large number of openingsv through which the steam is emitted.

In compliance with the requirements of the patent statutes I have here shown and described a preferred embodiment of my invention. It is, however, to be understood that the invention is not limited to the precise construction `here shown, the same being merely illustrative of the principles of' the invention.

What I consider new and desire to `secure by Letters Patent is:

l. In combination with a furnace having a draft intake and a nue gas outlet, duct means outside the furnace connecting the ue gas outlet with the said draft intake, fan means in said duct means for drawing flue gases from the outlet and delivering the gases to the said intake, means controlled by the furnace for controlling the fan, said duct means including also an opening for receiving atmospheric air, which opening is located between the fan means and the ue gas outlet, a damper in said duct means for connecting the fan inlet selectively to the flue gas outlet or to the air receiving opening, means `for supplying steam into said duct in advance of said fan, means for operating the damper to connect the inlet of the fan with the flue gas outlet, motor means dependent upon the supply of steam to said duct for operation of said damper operating means, and gravity operated means eective upon the non-operation of the motor means for closing the communication between the flue gas outlet and the portion of the'duct means leading to the fan.

2. In combination a steam generator, a furnace therefor having a draft intake and a fiue gas outlet, duct means outside of the furnace connecting the nue gas outlet with the said intake, fan means in said duct means for drawing hot flue gases from the outlet and delivering the gases to the said intake, a motor for driving the fan means, means controlled by the steam pressure for starting and stopping the motor, a damper in said duct means, means operative upon the attainment of a predetermined steam pressure for moving thedamper to open communication through said duct means and while the motor is in full operation, and means for automatically moving said damper to close communication through said duct means when the motor is not in operation.

3. In combination a steam generator, a fur nace therefor having a draft intake and a flue gas outlet, duct means outside of the furnace connecting the iiue gas outlet with the draft intake, fan means in said duct means for drawing hot ue gases from the outlet and delivering the gases to the draft intake, a motor for driving the fan means, means controlled by the steam pressure for starting and stopping the motor, a damper in said duct means, means operative upon the Aattainment of a predetermined steam pressure for moving the damper to open communication through said duct means and while the motor is in full operation and means for automatically moving said damper to close communication through said duct means when the motor is not in operation, said duct means including also an opening for receiving atmospheric air, which opening is located between the draft intake of the furnace and the damper whereby the damper prevents escape of flue gases through said air receiving opening.

4. In a smoke consuming apparatus for furnaces having provision for the formation of steam, means providing a mixing chamber, a duct for connecting said chamber with theexhaust gas outlet of the furnace, a second duct for connecting said chamber vwith the draft intake of the furnace, means for introducing steam and fresh air into said chamber simultaneously for intimate commingling with combustible parts of fuel products received in said chamber from said outlet, blower means connected with said second duct for withdrawing the mixture from said chamber and for forcing the same to the draft intake of the furnace, valve means for controlling the flow of steam to said chamber, valve means for controlling the oW of combustion products from said gas outlet to said draft intake, means operated by a characteristic of the steam formed by the furnace for closing the first one of said valve means, means for moving the other valve means toward closed position upon closing of the said first one of said valve means, and means for opening both of said valve means upon a predetermined variation in said steam characteristic.

5. In a smoke consuming apparatus for furnaces having provision for the formation of steam, means providing a mixing chamber, a duct for connecting said chamber with the exhaust gas outlet of the furnace, a second duct for connecting said chamber with the draft intake of the furnace, means for introducing steam and fresh air into said chamber simultaneously for intimate commingling with combustible parts of fuel products received in said chamber from said outlet, blower means connected with said second duct for withdrawing the mixture from said chamber and for forcing the same to the draft intake of the furnace, valve means for controlling the flow of steam to said chamber, valve means for controlling the flow of combustion products from said gas outlet to said draft intake, means operated by a predetermined rise in pressure of the steam formed bythe furnace for closing the first one of said valve means, gravity means for automatically moving the other valve means toward closed position upon closing of the said first one of said valve means, and means for opening both of said valve means upon a predetermined variation in said steam pressure.

GEORGE JOSEPTH BYRNE. 

